Magnetically actuated switches provide a compact, reliable and durable switching function. These switches offer a very slim profile, low weight and economical assembly. They combine the best features of mechanical and membrane switches. Particularly, they provide the tactile feel of a mechanical switch but with the superior durability of a conventional membrane switch. Without tactile feedback, consumers are not sure if they have activated the switch. Magnetically actuated switches provide the user with a switching sensation to indicate when the switch has been actuated while still providing the compactness of a membrane switch.
Magnetically actuated switches have the further capability of rotary, linear, or complex movement. As such, these switches have a nearly endless range of applications. However, the applicability of the magnetic switch can be expanded still further if the switches can be adapted to withstand high acceleration applications. For example, a switch undergoes abnormal acceleration when exposed to certain unintended activities such as being dropped. Planned activities such as rocket launches, subsonic aircraft flights and automobile accelerations can also subject switches to high loads.
A potential problem of magnetically actuated switches, particularly rotary switches, is that sudden accelerations may dislodge the magnetic bond within the switch. Unless the bond can be reestablished, the switch fails to work. So there is a need to provide a switch which will withstand high acceleration applications and maintain the magnetic attraction between the switch's internal components.
Another problem with magnetically actuated switches, as with membrane switches, is the presence of dust and debris within the switch. The debris may enter during manufacture of the switch or, alternatively, during normal wear of the switch. This debris may interfere with the switch contacts and may result in unpredictable switch performance. Hence, there is also a need to minimize the effect of debris on switch performance.